What is the difference between Medicare Advantage and a Medicare Supplement?

A Medicare Advantage plan provides your Part A and Part B benefits through a private Medicare-approved plan. Provider rules and costs vary, and many plans add benefits such as dental, vision or drug coverage. A Medigap policy works alongside Original Medicare to pay specified costs. Most policies work with providers nationwide who accept Medicare, though Medicare SELECT can use a network, and drug coverage is separate.

Which one is cheaper?

Neither structure is always cheaper. Medicare Advantage plan premiums, deductibles, copays and coinsurance vary, and you continue paying the Part B premium. Medigap adds a policy premium and usually a separate Part D premium, while the plan letter determines which Original Medicare cost-sharing amounts the policy pays.

Can I switch from Medicare Advantage to a Medicare Supplement?

You can leave Medicare Advantage for Original Medicare during an applicable election period, but that change does not automatically guarantee access to a Medigap policy. Outside your one-time 6-month Medigap Open Enrollment Period, an insurer may use medical underwriting unless a specific guaranteed-issue protection applies, such as certain first-time Medicare Advantage trial rights. Confirm your eligibility and the new policy's effective date before ending current coverage.

Which is better if I travel or live part of the year outside Arizona?

Most Medigap policies work with providers nationwide who accept Medicare, which can be useful for frequent travelers or seasonal residents. Medicare SELECT policies may use a network, while Medicare Advantage travel and out-of-area rules vary by plan, so confirm the details before enrolling.

Which is better if I want dental, vision and hearing included?

Many Medicare Advantage plans include dental, vision or hearing benefits, but coverage limits and provider rules vary. Medigap does not include those routine benefits; separate coverage may be available from an insurer or another provider.

How to choose

Medicare Advantage vs Medigap

These are two different structures, not two grades of the same thing. One provides Medicare benefits through a private plan; the other works alongside Original Medicare and helps pay specified costs.

The short answer

Medicare Advantage may fit if a plan’s provider rules, benefits and cost sharing suit your doctors, prescriptions and budget. Medigap may fit if you prefer Original Medicare’s provider access and are comfortable paying a separate policy premium. The right answer depends on the specific plans available to you, not the label alone.

Compare the details

What it does

Medicare Advantage (Part C): Provides your Part A and Part B benefits through a private Medicare-approved plan
Medicare Supplement (Medigap): Works alongside Original Medicare and helps pay specified out-of-pocket costs

Provider access

Medicare Advantage (Part C): Rules vary: HMOs generally require in-network care except in limited situations, while PPOs may cover eligible out-of-network care at a higher cost
Medicare Supplement (Medigap): Most policies work with providers nationwide who accept Medicare; Medicare SELECT policies may require a network for non-emergency care

Prescription coverage

Medicare Advantage (Part C): Most plans include Part D
Medicare Supplement (Medigap): Not included. You add a separate Part D plan

Extra benefits

Medicare Advantage (Part C): Often includes dental, vision and hearing benefits
Medicare Supplement (Medigap): Not included by Medigap; separate dental, vision or hearing coverage may be available

Monthly premium

Medicare Advantage (Part C): Premiums vary, including some $0-premium plans; you continue to pay your Part B premium
Medicare Supplement (Medigap): You pay a monthly premium for the Supplement, plus your Part D premium

Cost when you use care

Medicare Advantage (Part C): Deductibles, copays and coinsurance vary by plan, with an annual limit on covered Part A and Part B out-of-pocket costs
Medicare Supplement (Medigap): Depends on the plan letter; deductibles, copayments and non-covered costs may remain

When you can change it

Medicare Advantage (Part C): Annual Enrollment Oct 15 to Dec 7, one change in Open Enrollment Jan 1 to Mar 31, or a Special Election Period
Medicare Supplement (Medigap): The fall Annual Enrollment Period does not apply. Your one-time 6-month Medigap Open Enrollment Period starts when you are both 65 or older and enrolled in Part B; outside it, underwriting may apply unless you have a guaranteed-issue right

How carriers differ

Medicare Advantage (Part C): Networks, extras and costs vary plan by plan and change annually
Medicare Supplement (Medigap): Benefits are standardized within a plan letter, so carriers differ on price and service

Medicare Advantage compared with Medicare Supplement (Medigap)
	Medicare Advantage (Part C)	Medicare Supplement (Medigap)
What it does	Provides your Part A and Part B benefits through a private Medicare-approved plan	Works alongside Original Medicare and helps pay specified out-of-pocket costs
Provider access	Rules vary: HMOs generally require in-network care except in limited situations, while PPOs may cover eligible out-of-network care at a higher cost	Most policies work with providers nationwide who accept Medicare; Medicare SELECT policies may require a network for non-emergency care
Prescription coverage	Most plans include Part D	Not included. You add a separate Part D plan
Extra benefits	Often includes dental, vision and hearing benefits	Not included by Medigap; separate dental, vision or hearing coverage may be available
Monthly premium	Premiums vary, including some $0-premium plans; you continue to pay your Part B premium	You pay a monthly premium for the Supplement, plus your Part D premium
Cost when you use care	Deductibles, copays and coinsurance vary by plan, with an annual limit on covered Part A and Part B out-of-pocket costs	Depends on the plan letter; deductibles, copayments and non-covered costs may remain
When you can change it	Annual Enrollment Oct 15 to Dec 7, one change in Open Enrollment Jan 1 to Mar 31, or a Special Election Period	The fall Annual Enrollment Period does not apply. Your one-time 6-month Medigap Open Enrollment Period starts when you are both 65 or older and enrolled in Part B; outside it, underwriting may apply unless you have a guaranteed-issue right
How carriers differ	Networks, extras and costs vary plan by plan and change annually	Benefits are standardized within a plan letter, so carriers differ on price and service

Who each one tends to suit

Neither structure is better in the abstract. The right answer depends on your doctors, your prescriptions, your travel, and how you would rather pay: steadily every month, or at the point of care.

Medicare Advantage tends to fit when

Your doctors and specialists are already in the plan’s local network.
A plan you are considering includes extra benefits that fit your needs.
Its premium and cost sharing fit your monthly and point-of-care budget.
You stay in one area for most of the year.

A Medicare Supplement tends to fit when

You value the broad provider access available with most Medigap policies.
You travel, or spend part of the year outside Arizona.
You are willing to pay a policy premium for help with specified Original Medicare costs.
You see specialists often, or expect to.

The question that decides it more often than any other

In practice the comparison usually turns on two concrete facts about your life, not on the general merits of either structure: whether your specific doctors are in a given Advantage plan’s network, and how your specific prescriptions price out under each plan’s formulary. Both are checkable, and both change annually.

An independent agent can check those details across the carriers and plans the agent represents. Ask what is included in the comparison, then weigh the results against your doctors, prescriptions, travel and budget. CSG does not charge a separate fee for this comparison.

You are not locked in forever

You can change Medicare Advantage plans during the Annual Enrollment Period from October 15 through December 7. The Medicare Advantage Open Enrollment Period from January 1 through March 31 allows one Medicare Advantage plan change, or lets you drop Medicare Advantage to return to Original Medicare and add a Part D plan. Medigap does not use that same annual window: your one-time, six-month Medigap Open Enrollment Period starts the first month you are both 65 or older and enrolled in Part B. Outside it, an insurer may use medical underwriting, charge more or deny an application unless you have a guaranteed-issue right. Full detail is on our enrollment periods page.

Comparison questions

What is the difference between Medicare Advantage and a Medicare Supplement?: A Medicare Advantage plan provides your Part A and Part B benefits through a private Medicare-approved plan. Provider rules and costs vary, and many plans add benefits such as dental, vision or drug coverage. A Medigap policy works alongside Original Medicare to pay specified costs. Most policies work with providers nationwide who accept Medicare, though Medicare SELECT can use a network, and drug coverage is separate.
Which one is cheaper?: Neither structure is always cheaper. Medicare Advantage plan premiums, deductibles, copays and coinsurance vary, and you continue paying the Part B premium. Medigap adds a policy premium and usually a separate Part D premium, while the plan letter determines which Original Medicare cost-sharing amounts the policy pays.
Can I switch from Medicare Advantage to a Medicare Supplement?: You can leave Medicare Advantage for Original Medicare during an applicable election period, but that change does not automatically guarantee access to a Medigap policy. Outside your one-time 6-month Medigap Open Enrollment Period, an insurer may use medical underwriting unless a specific guaranteed-issue protection applies, such as certain first-time Medicare Advantage trial rights. Confirm your eligibility and the new policy's effective date before ending current coverage.
Which is better if I travel or live part of the year outside Arizona?: Most Medigap policies work with providers nationwide who accept Medicare, which can be useful for frequent travelers or seasonal residents. Medicare SELECT policies may use a network, while Medicare Advantage travel and out-of-area rules vary by plan, so confirm the details before enrolling.
Which is better if I want dental, vision and hearing included?: Many Medicare Advantage plans include dental, vision or hearing benefits, but coverage limits and provider rules vary. Medigap does not include those routine benefits; separate coverage may be available from an insurer or another provider.

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